Under-perception of asthma symptoms in children is a major risk factor for emergency department visits, hospitalizations, near-fatal and fatal asthma attacks. Puerto Rican and Black children have greater asthma morbidity and mortality rates than all other racial/ethnic groups. Interventions targeting asthma symptom perception and medication adherence may help to close the asthma health disparities gap in ethnic minority children. However, there is a paucity of literature on interventions to improve children's asthma symptom perception accuracy. This R01 study builds upon two of the PI's prior asthma symptom perception grants on ethnic minority, inner-city children with asthma. Children who saw their peak expiratory flow (PEF) after entering a PEF prediction on an electronic spirometer were less likely to under-perceive asthma symptoms and had greater adherence with controller medication use than children who did not see their PEF. The proposed double-blind, comparative effectiveness randomized controlled trial consists of two arms: PEF feedback (N = 130) versus control feedback (N = 130). Participants will include Latino and Black children with asthma ages 7-17 years old and their primary caregivers. Children will be recruited from clinics in the Bronx, NY. The primary aims are to examine the effectiveness of PEF prediction with feedback versus control feedback on 1) under-perception of asthma symptoms and 2) adherence to controller medications at post- intervention and across a 1-year follow-up, and 3) under-perception assessed in clinic, asthma control, and emergency health care use across a 1-year follow-up. An exploratory aim examines the hypothesized pathway that the intervention reduces under-perception of symptoms and increases children's and parents' asthma management self-efficacy, resulting in greater medication adherence and improved asthma control. Participants will complete a baseline visit followed by 3 weeks of PEF prediction without feedback using a programmable, electronic spirometer. Participants will then return to receive random group assignment by reprogramming their spirometer, showing either the actual PEF or a brief, positive message (Great job in remembering to use your peak flow meter!). For the next 6 weeks, all children will guess their PEF and receive feedback (actual PEF value or control feedback). Predictions of PEF will be locked in before children blow into the device. Participants will return for a post-intervention visit after 6 weeks, and the device reprogrammed to provide no feedback for the next 4 weeks to assess sustainability of effects. A 1-month post-intervention visit will take place to download the symptom perception data from home. Adherence to controller medications will be monitored by electronic devices. Additional follow-up sessions will take place at 3, 6, 9, and 12 months post-intervention to collect adherence data, conduct spirometry and assess asthma control, which will be rated by providers who are blinded to intervention group, using national guidelines. Medical record abstraction will compare emergency health care use for asthma between groups across the 12-month post-intervention period.